In 1976, Brookhaven National Laboratory initiated a program of external
radiation survey for the Rongelap, Rongerik, Ailuk, Wotje and Utirik Atolls.
The purpose of these surveys was to provide sufficient information concerning
the ambient radiation levels resulting from the mid 1950's weapons testing
program to make external dose calculations for the individuals living in the
surveyed areas.

During the last two years,

sufficient measurements were made

to provide external dose information for most of the populations in the region.
The data from Rongerik, Ailuk, Wotje, Rongelap and Utirik Atolls were
acquired during trips in September 1976, May 1977 and October 1977.

All the

exposure rate information gathered from these atolls was obtained with a pressurized ion chamber.
The equipment used in these studies consisted of a Reuter Stokes Environmental Radiation Monitor, Model RSS-111 and a gamma spectroscopy system consisting
of a sodium iodide detector coupled to a portable multichannel analyzer.

Environ-

mental exposure levels were assessed via the RSS-111, and the NaI gamma spectrometer was used to determine the energy dependence correction factors for the
RSS-111 instrument,
The field trips were staffed by BNL personnel and guest scientists from other
institutions.

Participants are listed later in the report.

This report represents all of the external exposure data collected to date by
BNL from these atolls.

From these data, we have made external exposure estimates

for the people living on Rongelap, Ailuk, Wotje and Utirik Atolls.

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